|an arrangement of five objects, as trees, in a square or rectangle, one at each corner and one in the middle.|
|a chattering or flighty, light-headed person.|
acetylcholine a·ce·tyl·cho·line (ə-sēt'l-kō'lēn')
A white crystalline derivative of choline that is released at the ends of nerve fibers in the somatic and parasympathetic nervous systems and is involved in the transmission of nerve impulses in the body.
|acetylcholine (ə-sēt'l-kō'lēn') Pronunciation Key
A substance that is released at the junction between neurons and skeletal muscle fibers, at the nerve endings of the parasympathetic nervous system, and across synapses in the central nervous system, where it acts as a neurotransmitter. Chemical formula: C7H16NO2.